63. tib fib

Question 1

Epiphysis of the tibia

Answer 1

–Proximal epiphysis–40%growth–Distal epiphysis–60%growth–Tibial tuberosity epiphysis (apophysis)–no growth, attaches to patellar ligament, closes late <12mo–Medial malleolus epiphysisTTepiphysis and proximal epiphysis fuse at 6-8monthsMMepiphysis and distal epiphysis fuse at 4-5months

Question 2

Fibulae head, body, and lateral malleolus

Answer 2

Head– lateral collateral of stifleLateral malleolus– lateral collateral of tarsus

Question 3

tibial tuberosity avulsions in young immature dogs

Answer 3

Occur due to extreme contraction of quadriceps muscleTxConservative (cast, splint) w minimal displacement only in small breed dog–2-3wkInternal fixation w pins alone(direct caudoproximal against pull of quadriceps) or pins/ tension band (preferred)Reattachment of patellar tendon achieved through tendon sutures thru ligament and transverse tibial bone tunnel (if patellar tendon ligament rupture)

Question 4

Tibial proximal physeal fractures

Answer 4

Salter Harris I and IIFrequently distal segment displaces craniomediallyTxCast/splint if minimal displacementMultidivergent pin fixation thru medial and lateral stifle approaches+/- interfragmentary screws if there is a large metaphyseal component

Question 5

Tibial metaphyseal fractures in mature animals

Answer 5

If minimal displacement, cast/splint or IM PINinternal fixation includes IM PINcross pininterfrag lag screwsplate(t plates, placed on side w comminution)ESF

Question 6

Types of fixation for diaphyseal tibial fractures

Answer 6

ESF(biological, good for open fx, limited muscle damage, dynamization)tie in IM pin/ESF — pin (50% diameter, inserted medial to patellar lig 1/3-1/2 from cranial to medial condyle) normograde avoids risk joint penetration IM pin + cerclage or lag screws if long oblique/spiral fx ( at least 2 cerclage placed at 1cm intervals)ILNPlates (contour, applied to medial tension side of tibia–compression, neutral, buttress)Plate-rod (rod 30-40% diameter, more rigid than ILN)MIPO

Question 7

Boone et al 1986 JAVMA Nonunion rate of 195 tibial diaphyseal fractures in dogs and cats

Answer 7

4.1%low, generally have good to excellent prognosis

Question 8

Malleolar fractures in mature animals

Answer 8

Frequently associated with tarsocural instability, check for collateral ligament injury; stress radsOften repaired with pins and tension band, pins alone, or lag screwsThe lateral malleolus of the distal fibula is fixed to the tibia

Question 9

Pes varus and pes valgus breed disposition

Answer 9

Pes varus–dachshund;eccentric medial closure of distal tibial physis, retarded medial growth, shortened, bow leggedSurgery tx w open wedge corrective osteotomy (ESF, PLATE)Pes valgus–Shetland sheepdogAbnormal growth of distal fibular physis Often both abnormalities present w patellar luxations

Question 10

malalignment or angular or rotational tibial deformity following tibial fracture repair

Answer 10

serious complication from inappropriate fixation techniques 1. IM pin (pin makes tibia too straight)2. medial bone plate fixation with under contouring3. implant failure with malunion (especially if plate is NOT on side of comminution)